3-D Printing Technologies in Advanced Gas Sensing: Materials, Fabrication, and Intended Applications: A Review

Printed gas sensors, predominantly fashioned from flexible materials, are rapidly emerging as pivotal tools for gas detection, holding immense promise for wearable applications. These sensors have carved a niche in gas detection and monitoring by harnessing cutting-edge materials and intricate printing methodologies. They operate based on principles of chemical absorption and electronic modulation (through changes in resistance), utilizing an array of nanomaterials such as graphene, metal oxides, and organic polymers to discern specific gas molecules with precision. This research explores avant-garde printing technologies, such as inkjet and screen printing, underscoring their efficacy in inaccurate material deposition across varied substrates. While their merits—scalability, cost-effectiveness, and adaptability—are manifold, inherent challenges related to durability, stability, and the subtle interplay between material attributes and detection sensitivity persist. Addressing the escalating demand for such sensors necessitates strategies for streamlined large-scale production. This manuscript holistically appraises the foundational principles, materials, and modalities intrinsic to printed gas sensors. Moreover, it sheds light on the prevailing challenges. It envisions the prospective innovations in this domain, highlighting the potential of these sensors to revolutionize the landscape of gas detection, particularly in wearable contexts.